1. Field of the Invention
The present invention relates to a navigation method,
The present invention further relates to a navigation system,
The present invention further relates to a navigation device,
The present invention further relates to a vehicle provided with a navigation device,
The present invention further relates to a group of vehicles.
2. Related Art
Nowadays GPS navigation facilities are available that can relatively accurately determine a position of a vehicle. However, in some circumstances alternative navigation methods are required as GPS-navigation signals are not always available, for example at locations below sea level and in buildings. One such alternative method applies dead-reckoning using data obtained from inertial sensors. Inertial sensors comprise gyroscopes and accelerometers. Gyroscopes provide information about the orientation of the vehicle and accelerometers provide information about its acceleration. If the initial position and velocity of a vehicle are known, its instantaneous velocity and position can be estimated by numerical integration of the acceleration and orientation data obtained from the accelerometers and gyroscopes. Generally accelerometers have a systematic error, also denoted as bias, resulting in a drift in position indication, exponential in time. Accordingly, such navigation devices based on inertial sensors need to be calibrated periodically to measure and compensate the sensor biases. With low-cost sensors, and without bias compensation, the navigation solution becomes useless within minutes. This also applies to dead reckoning methods using other sensors, e.g. odometers for measuring speed and a compass for measuring direction.
In “A distributed algorithm for cooperative navigation among multiple mobile robots” by Sanderson. Advanced robotics ISSN 0169-1864, 98, vol. 12, no 4, pp. 313-481 (17 ref.), pp. 335-349, a method is described for improving the navigation accuracy of robots by sensing of relative inter-robot positions and intercommunication of position estimates and planned trajectories. Although in this way a potentially better navigation result can be obtained than would be the case if the robots navigated independently, the method is complicated and the measurement of relative position may form another source of errors.
Accordingly, there is a need for improvement.